The Nation

Dairy Products Help Curb Risk Factors for Diabetes, Study Finds

Overweight people who consume lots of dairy products may be less likely to develop risk factors for diabetes, a study shows.

The findings, published in today's issue of the Journal of the American Medical Assn., pertain to insulin resistance syndrome, a condition that can lead to diabetes and that afflicts 1 in 4 Americans.

The body of an insulin-resistant person must produce an elevated level of insulin to control his or her blood sugar.

The study showed that for overweight people, eating dairy more than five times a day, as opposed to once, can reduce the risk of insulin resistance syndrome by 72%.

Insulin-resistant patients are at risk of developing Type 2 diabetes because of the heavy demand the syndrome puts on the pancreas. More pressing, some researchers believe, is the potential for heart disease.

A major risk factor for the syndrome is obesity, which changes the body's ability to use insulin. Concern is growing over the syndrome and diabetes because more Americans are obese than ever, said Mark Pereira, the study's lead author and an epidemiologist at Children's Hospital in Boston and Harvard Medical School. Younger and younger populations have developed insulin resistance syndrome in recent decades. At the same time, Pereira said, milk consumption has fallen and soda consumption has climbed. Studies show that dairy consumption and healthy body weights are linked, he said.

The researchers in the insulin resistance study analyzed data from another University of Minnesota study of coronary artery risk in young adults. That study followed more than 3,100 adults in four centers around the country for more than 10 years. The patients studied are now between the ages of 25 and 40.

For a patient to be considered insulin resistant, the researchers looked for two of four risk factors: abnormal glucose regulation, obesity, high blood pressure or dyslipidemia--which is high triglycerides (blood fats) and low "good" cholesterol levels (HDL).

People with the syndrome, also known as syndrome X or metabolic syndrome, often have high levels of triglycerides, as well as low HDL cholesterol and high blood pressure.

The researchers found a correlation between decreased dairy consumption and these factors related to insulin resistance syndrome.

Pereira and his group could not be certain precisely why dairy would prevent the syndrome. He said the nutrients in dairy products, such as calcium, might affect blood-sugar metabolism.

"Dairy has a really good mix of macronutrients" such as carbohydrates, proteins and fats, Pereira said. "They could fill people up more . . . than high-calorie, low-nutritional-value food," which might help prevent obesity.

The findings were met with some skepticism. Dr. Gerald Reavan, the Stanford University researcher who first described insulin resistance syndrome in the 1980s, questioned how the researchers diagnosed the syndrome.

Only half the people with the syndrome develop hypertension, Reavan said. A person can be obese and hypertensive, he said, and still not have the elevated insulin levels that define the syndrome.

He believes dyslipidemia is a better measure of the syndrome than hypertension, and said the effect of dairy on dyslipidemia in this study was not statistically significant.

Pereira said although not significant, eating five or more servings of dairy still had a notable effect on dyslipidemia, reducing the chance of its occurrence by a third.